Indian Ocean alkalinity

During a recent expedition in the Indian Ocean, as part of the WOCE Hydro-graphic Program, members of the U.S. DOE C02 Survey Science Team used these reference materials extensively for the quality control of measurements of total DIC and total alkalinity. Two manuscripts detailing the results of these measurements on reference materials were published describing the C02 measurements made on that expedition and how reference materials were used to assess the overall data quality (Johnson et al., 1998 Millero et al., 1998). 

Millero, F.J., A.G. Dickson, G. Eischeid, C. Goyet, P. Guenther, K.M. Johnson, K. Lee, D. Purkerson, D.L. Sabine, R.G. Schottle, D.R.W. Wallace, R.J. Wilke, and C.D. Winn. 1998. Total alkalinity measurements in the Indian Ocean during the WOCE hydro-graphic program C02 Cruises 1994-1996. Marine Chemistry 63(1-2) 9-20. 

Jeandel C., Dupre B., Lebaron G., Monnin C., and Minster J.-F. (1996) Longitudinal distributions of dissolved barium, silica and alkalinity in the western and southern Indian Ocean. Deep-Sea Res. 7 43, 1-31. 

Nozaki Y. and Yamamoto Y. (2001) Radium 228 based nitrate fluxes in the eastern Indian Ocean and the South China Sea and a silicon-induced alkalinity pump hypothesis. Global Biogeochem. Cycles 15, 555-567. 

They suggested that most of the carbonate dissolution in the deep ocean (Fig. 9.5) occurs within the sediments (85 %). The extension of their results from Pacific and Indian Ocean to the Atlantic Ocean leading to 120 10 molyr of global dissolved carbon fluxes from sediments may, however, be critical because of the completely different deep-water conditions in the Indo-Pacific and the Atlantic. Deep ocean waters in the Indian and Pacific Oceans are known to be much older and depleted in CO implying that a much higher proportion of calcite dissolution contributes to the total alkalinity input there. However, despite this problem of different bottom-... 

Figure 9 Comparison of the correlation of natural a C with silicate (A) and potential alkalinity (PALK = [alkalinity+ nitrate] x 35/salinity) (B) using the GEOSECS global data. Samples from high southern latitudes are excluded from the silicate relation. The presence of tritium was used to surmise the presence of bomb-A C. The somewhat anomalous high PALK values from the Indian Ocean are from upwelling-high productivity zones and may be influenced by nitrogen fixation and/or particle flux.

Fig. 10-20 Observed depth profiles of (a) phosphate, (b) dissolved inorganic carbon (TC), (c) alkalinity (TA), and (d) oxygen for the Atlantic, the Indian, and the Pacific Oceans as indicated. Data are from GEOSECS stations within 5° of the Equator in each ocean. (Modified from Baes et al. (1985).)...

Fig. 11-9 (a) The vertical distributions of alkalinity (Aik) and dissolved inorganic carbon (DIC) in the world oceans. Ocean regions shown are the North Atlantic (NA), South Atlantic (SA), Antarctic (AA), South Indian (SI), North Indian (NI), South Pacific (SP), and North Pacific (NP) oceans. (Modified with permission from T. Takahashi et ah, The alkalinity and total carbon dioxide concentration in the world oceans, in B. Bolin (1981). Carbon Cycle Modelling," pp. 276-277, John Wiley, Chichester.)... 

Figure 4.7. The mean vertical distribution of (a) alkalinity and (b) total CO2 concentration normalized to the mean world ocean salinity value of 34.78. NA = North Atlantic, SA = South Atlantic, NP = North Pacific, SP = South Pacific, NI = North Indian, SI = South Indian, and A A = Antarctic region. (After Takahashi etal., 1980b.)...

Cross sections of total alkalinity (A) and DIG (B) in the Atlantic, Indian and Pacific Oceans. Modified from the figure in Key et al. (2004). 

Depth profiles of total alkalinity (Aj) in the Atiantic, Antarctic, indian and Pacific Oceans. Piotted in Ocean Data View, using data from the e-WOCE compiiation. 

Figure 13. The vertical distribution of alkalinity (a) and dissolved inorganic carbon in the World s Ocean. Ocean regions are shown as NA (North Atlantic), SA (South Atlantic), AA (Antarctic). SI (South Indian), Nl (North Indian), SP (South Pacific) and NP (North Pacific) (Molten, 1992).

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